This application is from the Division of Neonatology at the University of Utah to join the Cooperative Multicenter Neonatal Research Network. The objective of the network is to foster rigorous clinical research on the care of newborn infants, particularly low birth weight infants, by providing sufficient patient availability to answer important clinical questions in a timely and powerful manner. The University of Utah NICUs are uniquely positioned to further these objectives. Specific strengths that the division proposes to bring to the network include: 1. The University of Utah Division of Neonatology NICUs have 1800 admissions from over 7500 deliveries annually. 2. The faculty is experienced in clinical research and eager to address the objectives exemplified by the Network. 3. The Division has long had a collegial and productive relationship with the Division of Maternal Fetal Medicine at the University, a division that has been an exemplary participant in the Maternal Fetal Medicine Network and shares data resources with the Division of Neonatology. Thus, the participation of this site in the Neonatal Network would benefit both networks. 4. Other resources available to the division include: a) the Utah Population Database and related databases, unique resources to investigate the genetic bases of newborn pathology;b) the Core Facilities Center at the University of Utah: c) the University of Utah GCRC;d) interaction with other research networks including the Pediatric Heart Disease Clinical Research Network, the Pediatric Emergency Care Applied Research Network, and the Pediatric Pharmacology Research Network;e) the Intermountain Center for Pediatric Nutrition Research;and the participation of Salt Lake County as a Vanguard Location and the University of Utah Department of Pediatrics as a possible Vanguard Center for the National Children's Study funded by NICHD. To show how these resources can be utilized by the network to answer important questions regarding the care of low birth weight infants, we propose a study testing the hypothesis that vasopressin will prove significantly better than dopamine for correction of hypotension occurring on the first day of life in VLBW infants requiring mechanical ventilation. In summary, this application from the Division of Neonatology at the University of Utah presents our commitment to use these resources in a cooperative and rigorous manner to further the mission of the NICHD Neonatal Research Network.